This invention relates to nibbling tools and more specifically to nibbling tools that incorporate a double-headed structure such that opposed die cutting ends can be alternatively utilized by the operator so that when the blade of one end becomes dull the other cutting end can be utilized simply by removing a handle covering or grip provided over one end to expose the alternate die cutting end and then utilizing the handle to cover the other cutting die end. Such double-ended tools can utilize either separate blades or punches or a single blade or punch. The present invention is directed to those tools utilizing a single punch. The handle is provided to enable the operator to grasp and manipulate the tool.
Nibbling tools have been available in various forms for many years and include those set forth in UK Patent No. 1,485,795 published Sep. 14, 1977; U.S. Pat. No. 4,489,492 issued Dec. 25, 1984; U.S. Pat. No. 4,748,744 issued Jun. 7, 1988 and U.S. Pat. No. 4,158,913 issued Jun. 26, 1979.
All of the above-noted patents disclose a nibbler tool that includes a single die cutting head and a punch or blade that reciprocates with respect to the die. The die has an entry area or slot for receipt of a sheet of material such as thin sheet metal and is provided with a cutting surface that cooperates with the punch or blade. During operation, the punch or blade reciprocates in a linear motion and cooperates with the die to bite or nibble a small crescent-shaped piece of material from the sheet with each punch stroke. As the operator's hands guide the tool, the nibbler tool cuts a slot in the desired direction.
More recently, nibbler tools incorporating a double-headed die structure have been introduced as above indicated. FIGS. 1 and 2 of the present drawings show the essential construction of one of such devices and in particular shows the construction of the reciprocating biter blade or punch housed within the structure itself. Although a decided improvement over single head nibbler tools, these double-headed nibble tools required considerable disassembly to install a new operating cutting punch or blade.
Accordingly, it is the object of the present invention to provide such double-headed nibbling tool structures with an improved blade assembly such that the blade can be easily removed with minimal disassembly and without requiring removal of either of the die heads or causing misalignment of the blade location block during such procedure. These and other objects of the present invention are accomplished by providing an elongated punch or blade having an extensive central portion of a uniform diameter that is equal to or slightly less than the diameter of the longitudinally oriented shaft or bore in which the blade is adapted to be received in the composite structure of the device. In this way, the replacement blade can be utilized to force the old and presumably dull blade out of the longitudinal bore while still maintaining contact with the blade location and drive block at all times such that misalignment thereof cannot occur and additionally afford a simple removal/installation procedure in the intended manner.
Other objects, features and advantages of the invention shall become apparent as the description thereof proceeds when considered in connection with the accompanying illustrative drawings.